Foundation ventilation system and method

ABSTRACT

A low voltage ventilating system and method of ventilating a crawl space of a building having a plurality of spaced apart crawl space vent openings formed in a wall of the crawl space is provided that and can be easily installed without the need for a professional electrician.

TECHNICAL FIELD

The invention relates generally to foundation ventilation systems andmethods of ventilating foundation areas.

BACKGROUND

Foundations of many buildings, such as buildings using pier and beamfoundations, are oftentimes provided with an air or crawl space thatunderlies the flooring or dwelling areas of the building. These spacesare usually provided with enough clearance between the ground andflooring to allow entrance therein to facilitate access to ducting,plumbing, etc. that may be located beneath the flooring of the building.

In many environments, these spaces may become damp or moist from themoisture in soils or seepage of water from the exterior portions of thebuilding. Additionally, during warmer periods, temperatures within thesespaces may be much cooler than the exterior temperatures. With highhumidity, these lower temperatures may result in the condensation ofmoisture in the air, increasing the dampness or moisture content ofthese spaces.

High moisture content within the crawlspace areas can be detrimental tothe building or its foundation. The moisture can facilitate the growthof mold and mildew. It can even result in the rotting or decay of woodenstructural elements, weakening the building or its foundation.

To facilitate ventilating of these spaces, most buildings are providedwith crawl space vent openings. These are usually in the form ofrectangular shaped openings formed in the foundation wall and merelyrely on natural convection or non-forced air flow through the openings.A screen may be positioned within the opening to allow air to flowthrough the opening, but preventing animals, insects, debris and otherobjects from passing through the opening. In many cases, the screen orvent openings may be provided with a closure that can be selectivelyopened and closed when conditions warrant.

To facilitate ventilation of these crawlspaces, fans or air movingdevices have been provided in these vent openings. Such prior artdevices, however, are usually hardwired into a wiring system of thebuilding. Such wiring systems are usually provided at a relatively highvoltage (egs. 120 V or more), requiring a professional electrician orsomeone skilled with such wiring systems to install the devices withoutcreating a risk of dangerous or lethal electric shock. Installation ofsuch ventilation devices is thus usually well outside the capabilitiesof most home owners.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying figures, in which:

FIG. 1 is a perspective view of a foundation wall of a building, showingremoval of an existing crawl space vent opening screen;

FIG. 2 is a perspective view of a ventilation fan assembly of aventilation system being installed within the vent opening of thefoundation wall of FIG. 1;

FIG. 3 is cross-sectional side view of the foundation wall of FIG. 2with the fan assembly installed within the vent opening;

FIG. 4 is a schematic representation of the ventilation system,constructed in accordance with the invention;

FIG. 5 is a cross-sectional plan view of a foundation wall of a crawlspace of a building with the ventilation system installed; and

FIG. 6 is a non-vent-opening fan assembly for use with the ventilationsystem.

DETAILED DESCRIPTION

Referring to FIG. 1, an exterior foundation wall 10 of a crawl space ofa building is shown. The wall 10 is provided with one or more crawlspace vent openings 12 to allow the passage of air between the exteriorand interior of the crawl space. The openings 12 are typicallyrectangular in shape and may be of standardized dimensions (egs. 8″×16″)to facilitate mounting of pre-manufactured vent screens, such as thevent screen 14. The vent screen 14 may substantially fill the opening12. The screen 14 may be fixed within the opening 12 along one or moreedges of the perimeter 16 using mortar or caulking 18 or other fasteningor securing means.

Referring to FIG. 2, a fan assembly unit 20 is shown that may bepositioned within a crawl space vent opening, such as the opening 12,and may be used to replace the screen 14. The fan assembly unit 20includes a main frame or housing body 22, which is received within theopening 12, as shown in FIG. 3. The housing body 22 may have a generallyrectangular “box-like” configuration with transverse upper and lowerwalls that are joined together by opposite left and right uprightsidewalls to define an interior of the housing 22 for allowing passageof air therethrough. An outwardly projecting lip or rim 24 may beprovided along the forward portion of the housing body 22. Therelatively thin lip or rim 24 extends around the forward perimeter ofthe housing body 22 and has a rearward surface 26 (FIG. 3) that maygenerally abut against the exterior portion of the wall 10 immediatelysurrounding the opening 12 when the unit 20 is positioned therein.

Mounting screws or fasteners 27 may be provided in the forward portionof the housing body 22 to facilitate securing the fan assembly unit 20within the opening 12. Such screws or fasteners 27 engage the perimeter16.

The fan assembly 20 is provided with one or more low voltage fans 28.The fans used for each fan assembly may provide a total air flowcapacity of from about 50 to about 500 cfm, more particularly from about100 to about 500 cfm, and still more particularly from about 150 toabout 300 cfm. In the embodiment shown, a pair of low voltage axial flowfans 28 is used. An example of a commercially available low voltage fanhaving about a 100 cfm capacity is that available as Commonwealth™ ModelFP-108/DC Brushless Fan, which has a capacity of about 98 cfm. Anexample of commercially available low voltage fan having a capacity ofabout 200 cfm at 16.8 watts is that available as the Model No.D17251V12M, from Symbang International, Inc., Taiwan. Other low voltagefans having the same or different capacities are also commerciallyavailable.

As used herein, the expression “low voltage” is meant to encompass avoltage of less than 60 volts. In particular, low voltage may include avoltage of less than 50 volts, more particularly less than 30 volts, andmay include a voltage of about 12 volts or 24 volts, which is used forlow voltage systems that are in commonly employed within the UnitedStates today. Low voltage may include that which may be readily employedwith wiring of 16, 18 gauge or smaller diameter wire. The low voltagemay not create dangerous or lethal electric shock upon exposure.

The fan or fans 28 are mounted to the main housing 22 and may be housedwithin a fan housing 30. The fan housing 30 may include a screen orother device that allows passage of air therethrough and that mayprevent matter or other objects from passing through the interior of thehousing 30 from the rear and into contact with the fans 28.

A set of louvers or other closure 32 may be mounted to and housed withinthe housing 22. The closure 32 may be selectively closed or opened toallow or prevent passage of air through the interior of the housing 22.A lever or other mechanism 34 may be provided to facilitate opening andclosing of the closure 32 from the exterior side of the foundation wall10 when the fan assembly 20 is mounted therein.

A forward grate or screen 36 may also be provided that generally extendsacross the housing interior and prevents the passage of objects andmatter through the front of the housing 30. The grate or screen 36 maybe recessed slightly from the forward edge of the housing 22. Asecondary screen 38 may also be provided that extends across the housinginterior to the rear of the grate 36. The secondary screen 38 may havesmaller openings or be of finer mesh screen to prevent the passage ofsmaller objects or material through the housing interior.

A low voltage tap wire assembly 40 is provided with the fan assembly 20.The wire assembly 40 includes a length of low voltage electrical cord 42that is coupled at one end to the low voltage fan or fans 28 forsupplying electrical power thereto. The cord 42 may have a length offrom about 1 to about 5 feet. A selectively-positionable electricalconnector 44 (FIG. 4) is also provided at the opposite end of the cord42. The connector 44 may include an insulation penetrating connector. Anexample of such a connector is that commercially available as 3M™Scotchlok™ 560 Insulation Displacement Connector (IDC), Double Run orTap connector, available from 3M Company. The connectors 44 are thosethat can be positioned generally anywhere along the continuous length ofa low voltage electrical cord (run wire) without cutting of the cord towhich they connect and while still making an electrical connection forthe passage of current between the electrical cords or wires (run andtap) that are being joined together and that may still provideinsulation for the connection.

Referring to FIG. 4, a ventilation system 46 is shown that incorporatesthree of the fan assemblies 20, as previously described. The system 46includes a single, high-voltage electrical cord 48 having a plug 50 atone end for plugging into an electrical outlet of an exterior electricalsocket connected to high voltage power source associated with thebuilding for which the ventilation system 46 is being used. The highvoltage power source may include a 120 volt system, which are commonlyemployed in buildings or dwellings within the United States.

Coupled to the high voltage cord 48 opposite the plug 50 is a voltagereducing device 52, such as voltage transformer. The device 52 mayinclude a 12 volt DC transformer for reducing the voltage from and alsofor converting AC current to DC, if desired. An example of a suitablecommercially available voltage reducing device is the Malibu ML80Ptransformer, available from Intermatic, Inc.

The voltage reducing device 52 locates exterior to the wall 10 and tothe crawlspace. The device 52 provides a low voltage output that isconducted by means of low voltage wire or cord 53 to a controller 54,which is also located exterior of the crawlspace. The controller 54 isprovided with temperature and humidity sensors 56, 58 for measuring andmonitoring temperature and humidity conditions exterior to crawlspaceinterior. Additionally, a timer may also be provided with the controller54.

The device 52 also provides a low voltage electrical output through alength of low voltage electrical cord 60 for conducting electricalcurrent to the fan assemblies 20. This may be coupled through thecontroller 54 so that the controller 54 regulates the current from thetransformer 52 that is supplied through the cord 60. The cord 60 may beof 16, 18 gauge or smaller gauge wire suitable for use with low voltageelectrical current. The cord 60 may be continuous and have a substantiallength so that it may extend to spaced apart vent openings into whichthe fan assemblies may be mounted. This may be at least 25, 30, 40, 50,100 feet or more. The cord 60 may initially be provided on a spool orother device (not shown) to facilitate storing of the cord prior toinstallation.

The low voltage cord 60 may be passed through the interior of the fanassembly housing 22 of one of the fan assemblies 20. A small passage oropening (not shown) formed in the screens or covers of the fan assemblyhousing may be provided to facilitate passage of the cord 60 in thismanner. Alternatively, the low voltage cord 60 may be passed through asmall hole or opening formed in the foundation wall 10, as shown inFIGS. 2 and 3. This may be near or adjacent an exterior electricalsocket of the building to which the system is to be plugged.

The ventilation system 46 may be provided as a kit with the requiredcomponents for ventilation of the crawl space of a dwelling or buildingprepackaged. The kit may be provided with each of the componentsdiscussed above, and may include 2, 3, 4 or more fan assemblies 20. Theventilation system kit may be provided with a varying number of fanassemblies in each kit based upon the square footage of the building ordwelling crawlspace for which it is intended to be used. Severaldifferent prepackaged kits may be provided for use with buildings ordwellings of different sizes. The ventilation system or kit may beinstalled with minimal effort without requiring a professionalelectrician or one highly skilled with electrical wiring. Instructionson installation that may generally follow along the description whichfollows may be provided with the kit.

The number of fan assemblies provided with the kit or to be used withthe ventilation system may be based upon the amount of air that needs tobe circulated through the crawlspace. A ventilation system thatcirculates one crawlspace volume of air every 3 to 15 minutes or moremay be suitable. As an example, an 1800 square foot crawlspace having acrawlspace height of approximately 3 feet would have a crawlspace volumeof about 5400 ft³. A ventilation system with four fan assemblies 20having a flow capacity of about 200 cfm each would thus circulate a 5400ft³ volume of air every 6.75 minutes. With five fan assemblies 20 at 200cfm each, the 5400 ft³ volume of air would be circulated every 5.4minutes.

Installation of the ventilation system 46 may be carried out as follows.A determination is made of the number and location of crawl space ventopenings 12 of the building or dwelling for which the ventilation systemis to be installed. Additionally, it may be desirable to determine theapproximate square footage of the crawlspace. One fan assembly may beused for each approximately 300 to 600 square feet, or moreparticularly, each approximately 400 to 500 square feet area. Thus, foran 1800 square foot crawlspace, approximately 3 to 6 fan assemblies maybe used, more particularly 4 to 5 fan assemblies. This may varydepending upon the available vent openings 12, however.

Referring to FIG. 5, the fan assemblies are preferably placed generallyon one side of the building or dwelling. Vent openings opposite thesewill be free of any fan assemblies, but may be left opening tofacilitate cross ventilation and introduction of fresh exterior air, asshown by the arrows 62.

Upon a determination of which vent openings 12 will be provided with thefan assemblies 20, any existing screen, such as the screen 14, isremoved. Any existing mortar or caulking 18 that may surround the screento secure it within the opening 12, may be removed, as shown in FIG. 1.The fan assemblies 20 are then mounted into the selected vent openings12, with the tap assemblies 40 passing through the rear of the opening12 into the interior of the crawl space. When placed within the openings12, the lip or rim 24 will abut against the exterior of the foundationwall 10 immediately surrounding the opening 12 to provide a generallyflush and finished appearance. The screws or fasteners 27 may then betightened or engaged to fix the fan assemblies in place within theopenings 12.

A high voltage exterior electrical outlet is located to which the plug50 may be plugged. If the electrical outlet is located adjacent to onethe screen openings 12 to which the fan assembly will be mounted, theconfiguration wherein the cord 60 passes through the housing 22 (notshown) may be used. Alternatively, in situations where the exteriorelectrical outlet is remote from such a screen opening, a small hole(FIGS. 2 and 3) may be drilled through the wall 10 adjacent to theelectrical outlet. The end of the cord 60 may then be passed through theformed hole or opening formed in the wall 10 and into the interior ofthe crawl space. The cord 48 should remain unplugged from the exteriorelectrical outlet until installation is complete and the ventilationsystem is ready to be operated.

The transformer 52 and attached controller 54 may be positioned adjacentthe wall 10 exterior of the crawl space. The low voltage cord 60 is thenpassed or extended into the interior of the crawl space to reachadjacent to each of the vent openings to which the fan assemblies 20 aremounted so that the cord 42 may be electrically coupled to the cord 60.

The fan assembly cord 42 for each fan assembly 20 is tapped or coupledto the low voltage cord 60 by means of the connectors 44. The connectors44 may make electrical connection between the conductors of the cords 60without requiring any stripping or exposing of the insulationsurrounding the wire. The connectors 44 may be secured by merelycrimping with a pliers or other crimping device so that the contact ofsuch connector 44 pierces or penetrates the insulation and makes contactwith the conductors of both the tap and run wires, without requiringstripping or cutting of the cord 60. This is done for each of the fanassembly units 20.

When each of the fan assemblies 20 is electrically connected to the cord60, the ventilation system 46 is installed. The plug 50 may be pluggedinto the high voltage electrical outlet associated with the buildingwhere the transformer 52 reduces the power output to the controller 54to a low voltage output.

The controller 54 regulates the low voltage output to the fan assemblies20 through the cord 60. The controller 54 senses outside temperature andhumidity conditions by means of thermostat and humidistat 56, 58. As anexample of one mode of operation, when exterior temperatures sensed bythe thermostat 56 are above about 40° F. and relative humidity is below80%, current is provided to power the fans 28. Such temperature andhumidity settings may be varied, however. This causes air to be forciblyexpelled through the vent openings 12. Air is also drawn into thenon-modified vent openings 12A, 12B, 12C that are free of fanassemblies, as shown FIG. 5.

When the exterior temperature drops below 40° F. or the humidity risesabove 80%, the controller 54 causes power to the fan assemblies 20 to becut off. This prevents cold or humid exterior air from being drawn intothe crawl space, such as through the non-modified vent openings 12A,12B, 12C. Additionally, the louvers 32 may also be closed to preventpassage of air through the interior of the housing.

In another embodiment, a timer (not shown) may be provided with thecontroller 54. The timer may be set so that the fans are powered atcertain times of the day, such as during the day when exterior airtemperature may be warmer or less humid.

Referring to FIG. 6, a non-vent-opening fan assembly 64 is shown. Thenon-vent-opening fan assembly 64 is provided with a low voltage fan orfans 66, which may be similar to the fans 28 of the fan assemblies 20.The fan 66 is joined to an arm 68 that may have a bracket 70 or othermounting means configured for coupling or securing to floor joist 72 orother structural element of the crawl space. The assembly 64 may also bestaked in earth or soil of the crawl space or be otherwise supportedthereon. The fan assembly 64 may be coupled to the low voltageelectrical cord or wiring 60 in a manner similar to the fan assemblies20. The fan assembly 64 is provided with a tap assembly 74, which may besimilar to the tap assembly 40, to accomplish this. One or more of suchnon-vent opening fan assemblies 64 may be secured in such fashion aspart of the ventilation system 46 and may be provided as part of theprepackaged ventilation system kit, as well.

The non-vent-opening fan assemblies 64 may be positioned in areas orpockets of dead air space that may be located under the crawl space orother areas of the building or dwelling. These areas may be remote fromany vent openings 12 and may be isolated from cross flow air or air thatis drawn by the fan assemblies 20. The fan assemblies 64 may bepositioned and directed to facilitate the movement of air out of theseareas or pockets into the air stream drawn by the fan assemblies 20 ofthe vent openings 12.

In another configuration and mode of operation, the non-vent-opening fanassemblies 64 may be used in place of the fan assemblies 20. In such aconfiguration, one or more fan assemblies 64 may be positioned near oradjacent to existing vent openings 12 by attaching them to a joist orother structural member of the crawl space or by staking or beingotherwise supported thereon. The vent openings 12 may be provided with avent screen, such as the conventional vent screen 14 of FIG. 1. The fanassemblies 64 may be arranged similarly to the fan assemblies 20, asshown in FIG. 5, generally along one side of the building crawl space toprovide cross ventilation, as previously discussed. The fan assemblies64 may thus direct air through the openings 12 without the removal ofany existing screen or preexisting structure that may be located withinthe vent opening. Such ventilation system employing the fan assemblies64 instead of the fan assemblies 20 may be operated and assembled in asimilar manner to the ventilation system 46, incorporating thecontroller 54, voltage reducing device 52, etc.

While the invention has been shown in only some of its forms, it shouldbe apparent to those skilled in the art that it is not so limited, butis susceptible to various changes and modifications without departingfrom the scope of the invention. Accordingly, it is appropriate that theappended claims be construed broadly and in a manner consistent with thescope of the invention.

1. A method of ventilating the crawl space of a building having aplurality of spaced apart crawl space vent openings formed in a wall ofthe crawl space, the method comprising: positioning fan assemblieswithin at least two spaced apart crawl space vent openings, each fanassembly having a low voltage fan and a fan housing configured to bereceived within one of the crawl space vent openings; providing a singlehigh voltage electrical cord having a plug at one end for being receivedwithin an exterior electrical socket of a high voltage power sourceassociated with the building; providing a voltage reducing devicelocated exterior to the crawl space that is coupled to the high voltagecord for converting high voltage from the high voltage power source to alow voltage output; providing a continuous length of low voltageelectrical cord coupled to the voltage reducing device for receiving andconducting the low voltage output from the voltage reducing device;extending the length of low voltage electrical cord to areas adjacent tothe at least two spaced apart crawl space vent openings; coupling thefan assemblies to the length of low electrical cord with a tap assemblythat includes a length of electrical tap cord that is connected at oneend to the low voltage fan and a selectively-positionable connector thatconnects the other end of the tap cord to the length of low voltageelectrical cord to provide electrical connection therewith; andselectively operating the fan assemblies to draw air through the atleast two spaced apart vent openings upon reaching at least one ofselected time, temperature and humidity conditions within the crawlspace.
 2. The method of claim 1, wherein: positioning the fan assembliesincludes removing any existing covering of the at least two of the crawlspace vent openings.
 3. The method of claim 1, wherein: the connector isan insulation penetrating connector that can be positioned generallyanywhere along the length of the low voltage electrical cord withoutcutting.
 4. The method of claim 1, wherein: selectively operating thefan assemblies includes providing an exterior located controller coupledto the voltage reducing device and receiving the low voltage output, thecontroller having temperature and humidity sensors located exterior tothe crawlspace.
 5. The method of claim 1, further comprising: providinga non-vent-opening fan assembly for mounting to a non-vent-opening crawlspace structure, the non-vent-opening fan assembly coupling to the lowvoltage electrical cord by a tap assembly.
 6. The method of claim 1,wherein: extending the length of low voltage electrical cord to areasadjacent to the two spaced apart crawl space vent openings includesextending the low voltage electrical cord within the interior of thecrawl space.
 7. The method of claim 1, wherein: providing a low voltageelectrical cord includes passing the low voltage electrical cord throughan exterior wall of the crawl space.
 8. A ventilation system for a crawlspace of a building having a plurality of spaced apart crawl space ventopenings formed in a wall of the crawl space, the ventilation systemcomprising: a single high voltage electrical cord having a plug at oneend for being received within an exterior electrical socket of a highvoltage power source associated with the building; a voltage reducingdevice coupled to the high voltage cord for locating at a positionexterior to the crawl space for converting high voltage from the highvoltage power source to a low voltage output; a continuous length of lowvoltage electrical cord coupled to the voltage reducing device forreceiving and conducting the low voltage output from the voltagereducing device; at least two fan assemblies, each fan assembly having alow voltage fan and a fan housing configured to be received within onecrawl space vent opening; and at least two tap assemblies, each tapassembly including a length of electrical tap cord that connects at oneend to the low voltage fan of one of the at least two fan assemblies anda selectively-positionable connector that connects the other end of thetap cord to the length of low voltage electrical cord at a selectedposition along the length of the low voltage electrical cord to provideelectrical connection therewith.
 9. The ventilation system of claim 8,wherein: the connector is an insulation penetrating connector.
 10. Theventilation system of claim 8, further comprising: a controller coupledto the voltage reducing device and receiving the low voltage output, thecontroller being located exterior to the crawl space and controlling theoperation of the low voltage fan assemblies.
 11. The ventilation systemof claim 10, wherein: the controller includes at least one of a timer, athermostat and a humidistat.
 12. The ventilation system of claim 10,wherein: the controller includes temperature and humidity sensors. 13.The ventilation system of claim 8, further comprising: anon-vent-opening fan assembly for mounting to a non-vent-opening crawlspace structure, the non-vent-opening fan assembly coupling to the lowvoltage electrical cord by a tap assembly.
 14. A ventilation system kitfor a crawl space of a building having a plurality of spaced apart crawlspace vent openings formed in a wall of the crawl space, the ventilationsystem kit comprising: a single high voltage electrical cord having aplug for being received within an exterior electrical socket of a highvoltage power source associated with the building; a voltage reducingdevice coupled to the high voltage cord for locating in a positionexterior to the crawlspace for converting high voltage from the highvoltage power source to a low voltage output; a continuous length of lowvoltage electrical cord coupled to the voltage reducing device forreceiving and conducting the low voltage output from the voltagereducing device, the low voltage electrical cord having a length of atleast 25 feet; at least two fan assemblies, each fan assembly having alow voltage fan and a fan housing configured to be received within onecrawl space vent opening, each fan assembly having attachment membersfor engaging the vent opening to facilitate securing the fan assemblythereto; at least two tap assemblies, each tap assembly including alength of electrical tap cord that connects at one end to the lowvoltage fan of one of the at least two fan assemblies and aselectively-positionable connector that connects the other end of thetap cord to the length of low voltage electrical cord at a selectedposition along the length to provide electrical connection therewith;and a controller, which includes temperature and humidity sensors,coupled to the voltage reducing device for receiving the low voltageoutput, the controller locating in a position exterior to the crawlspace and controlling the operation of the low voltage fan assemblies.15. The ventilation system of claim 14, wherein: the connector is aninsulation penetrating connector that can be positioned generallyanywhere along the length of the low voltage electrical cord withoutcutting.
 16. The ventilation system of claim 14, further comprising: anon-vent-opening fan assembly for mounting to a non-vent-opening crawlspace structure, the non-vent opening fan assembly coupling to the lowvoltage electrical cord by a tap assembly.